Macrocell corrosion in carbonated Portland and Portland-fly ash concrete - Contribution and mechanism

The corrosion of reinforcement in carbonated concrete with high moisture state was measured with and without electrical connection to reinforcement in non-carbonated concrete. The impact of the fly ash content and the cathode-to-anode ratio (C/A) was studied. A model was proposed and applied to quantify the contribution of the anodic, cathodic and ohmic partial processes to the macrocell corrosion and the impact of C/A. The total current density for the high moisture state investigated was high in all cases regardless the amount of fly ash replacement. The governing partial process depended on the cathode-to-anode ratio.